A novel method for determination and quantification of 4-methyloctanoic and 4-methylnonanoic acids in mutton by hollow fiber supported liquid membrane extraction coupled with gas chromatography

• Published in: Meat science 2012-12, Vol.92 (4), p.715-720
• Main Authors: Chen, Haigui, Wang, Yunfan, Jiang, Houyang, Zhao, Guohua
• Format: Article
• Language: English
• Subjects: Animals; Biological and medical sciences; Branched fatty acids; Caprylates - adverse effects; Caprylates - analysis; Caprylates - isolation & purification; China; Determination; Diet - ethnology; Exudates and Transudates - chemistry; Fatty Acids - adverse effects; Fatty Acids - analysis; Fatty Acids - isolation & purification; Flame Ionization; Food Contamination; Food engineering; Food industries; Food Inspection - methods; Frozen Foods - analysis; Frozen Foods - economics; Fundamental and applied biological sciences. Psychology; Gas chromatography; General aspects; Hollow fiber supported liquid membrane extraction; Limit of Detection; Male; Meat - analysis; Meat - economics; Meat and meat product industries; Odorants; Pheromones - adverse effects; Pheromones - analysis; Pheromones - isolation & purification; Reproducibility of Results; Sensation; Sheep, Domestic - metabolism; Solvents - chemistry; Sweaty odor; Tissue Extracts - chemistry; Tissue Extracts - isolation & purification
• ISSN: 0309-1740; 1873-4138
• DOI: 10.1016/j.meatsci.2012.06.027

4-methyloctanoic acid (MOA) and 4-methylnonanoic acid (MNA) are the main compounds responsible for “sweaty” odor of mutton. A novel method for their determination has been developed and validated. Hollow fiber supported liquid membrane (HF-SLM) was applied to selectively extract MOA and MNA prior to gas chromatography (GC) analysis. For HF-SLM, the donor outside the fiber was the acidified supernatant (pH 4) from aqueous mutton slurry. Liquid membrane was 5% tri-n-octylphoshphine oxide in di-n-hexyl ether and 0.3M NaOH aqueous solution filled in the lumen of the fiber was used as the acceptor. The extraction last for 4h. After acidification with HCl, the acceptor was directly analyzed by GC. Importantly, HF-SLM provided high enrichment factors for MOA (133) and MNA (116). The method developed had low detection limits of 0.0007–0.0015mg/kg, good linearity (R2>0.9956), reasonable recovery (88.54–122.13%), satisfactory intra-assay (7.83–9.73%) and inter-assay (15.68–16.14%) precision. ► HF-SLM selectively extracted 4-methyloctanoic and 4-methylnonanoic acids. ► HF-SLM highly enriched 4-methyloctanoic and 4-methylnonanoic acids up to 110 folds. ► HF-SLM-GC approved determination of trace amounts of mutton sweaty odor compounds.